Butler Still Doesn't Know What Rubin Did on Black Sabbath's '13

He called the producer's way of thinking 'ridiculous.'

Black Sabbath share an inside look at the recording of their new album - Fact Magazine

Geezer Butler - Far Out Magazine

Black Sabbath emerges from the dark with new album

Black Sabbath Set Release Date for '13' Album produced by Rick Rubin

Black Sabbath: 'We used to have cocaine flown in by private plane', Black Sabbath

Geezer Butler on Working with Rick Rubin on Black Sabbath's 13: “I Still Don't Know What He Did”

Geezer Butler talks Black Sabbath, bass playing and The End

Unsung Melody - My experience. The exclusive listening party for Black Sabbath's 13

Into the Void by Geezer Butler - Audiobook

Timeline Page – Black Sabbath Online